Windows 7 why wont my windows take automatic updates

I have a 6 year old acer that is 64 bit system... I lost my Ultimate 7 64 bit disk and downloaded from digital river the iso. I entered the product key and everything goes through fine but when I try getting the automatic updates my computer will not download and just endlessly search for these updates. I even downloaded service pack 1 and still to no avail I dont get the 300 plus security updates. My friend leant me his 32 bit original disk and all the updates do download and install. Can anyone tell me is there something wrong with digital rivers and sonrays iso copy. I cannot get the 64 bit iso from microsoft cuz my computer came with the software and microsoft will not give me their version. Also I would like to know am I compromising the way my computer works by just running the 32 bit version?? Please help anyone.... I feel im going crazy and am losing so much sleep trying to troubleshoot this issue